Pericardium reinforcing devices and methods for using them

ABSTRACT

A surgical device for reinforcing the pericardial sac surrounding the heart to assist in the treatment of congestive heart failure includes an enclosure having an interior and an exterior. The interior surface limits adhesions or accepts ingrowth with the myocardial tissue of the epicardium. The exterior surface is adapted to adhere to or otherwise attach to the pericardium to provide reinformcement.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.09/963,848 (Attorney Docket No. 020979-002400US), filed Sep. 25, 2001,the full disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to surgical devices and to methods of using them.In particular, the device is one for reinforcing the pericardial sacsurrounding the heart to assist in the treatment of congestive heartfailure. The device, generically, is an enclosure having an interior andan exterior. The interior surface is made in such a way that it tendsnot to or does not form adhesions with or accept ingrowth with themyocardial tissue of the epicardium. The exterior surface of the device,in contrast, is adapted to adhere to or to ingrow with or otherwise toattach sufficiently to the pericardium so that it reinforces thatmembrane or structure. The nature of the device is that it tends not toallow the pericardium to expand further with time. The device, aftercomplete deployment, desirably envelopes some measure of pericardialfluid in its interior separating it from the epicardial surface. Thisdevice helps to prevent further declination of the condition of theheart during the course of congestive heart failure. The device ispreferably introduced into the pericardial space and onto the innersurface of the pericardium using transcutaneous or minimally invasivetechniques.

Congestive Heart Failure (“CHF”), or simply “Heart Failure” is aprogressive path found in many forms of heart disease. In general, it isa condition in which the heart is unable to pump blood at a ratesufficient for the proper supply of nutrients to metabolizing tissues.There are many specific disease states leading to CHF, but eachtypically results in the dilatation of the ventricles. Variousetiologies for CHF are viral and ischemic and, of course, idiopathic.Myocardial injury and chronic volume overload generally are thought tocause this course of ventricular dilatation. The typical adaptationprocess undertaken by the stressed heart muscle is not achieved duringCHF and, instead of gaining a stronger heart muscle, the heart insteadgets larger as it attempts to adapt to its increased volume load.

Chronic pressure overload causes another response mechanism to develop.Specifically, hypertrophy of the heart muscle, entailing an increaseboth in the size of individual muscle cells and in overall muscle mass,begins to occur. Although this response helps the heart to overcomehigher pressure, it has limitations and is associated with variousstructural and biochemical changes that have deleterious long termeffects.

Additionally, system-wide vascular constriction occurs during the courseof CHF. The constriction causes blood flow to be redistributed so thatcertain regions and systems have a reduced blood supply, e.g., skeletalmuscle, kidneys, and skin. These regions do not produce significantamounts of vasodilating metabolites. In contrast, the brain and hearthave high metabolic rates and produce a greater amount of vasodilators.Consequently, the latter organs receives a higher proportion of therestricted blood supply.

Therapy for CHF is staged. Correction of a reversible causative factorsis the first line of offense. Treatment of bradyarrhythmias, perhaps byuse of an artificial pacemaker or by provision of an appropriate drugsuch as digitalis, can help alleviate CHF. CHF that continues aftercorrection of such reversible causes is often treated with a regime ofsalt restriction, vasodilators, diuretics, and the like. Bed rest toincrease venous return to the heart and move fluid from the periphery isoften helpful. As noted above, digitalis has been an important drug forincreasing cardiac output in persons with specific types of CHF. It hasbeen used for over 200 years. Other drugs used for treatment of CHFinclude beta-adrenergic agonists such as norepinephrine, epinephrine,and isoproterenol. Each stimulate cardiac beta-adrenergic receptors.Dopamine and dobutamine are also used. Various diuretics andvasodilators for variously dilating both veins and arteries are used,each for slightly different reasons based on the detected manifestationof the CHF in the heart. Few interventional or surgical pathways foralleviation of CHF are currently widely practiced. Indeed, the onlypermanent treatment for CHF is a heart transplant.

One surgical procedure known as cardiomyoplasty is used for early stageCHF. In that procedure, a muscle taken from the shoulder (the latissimusdorsi) is wrapped around the heart. The added muscle is pacedsynchronously with the ventricular systole. This procedure is highlyinvasive requiring a stemotomy to access the heart. Some have suggestedthat the benefits of the procedure are due more to remodeling from themere placement of the shoulder muscle around the heart rather than froma muscular assistance.

There are a variety of devices that may be applied to the heart fortreatment of CHF. Patents owned by Abiomed (U.S. Pat. Nos. 6,224,540;5,800,528; 5,643,172) generally show a girdle-like device situated toprovide structure to a failing heart. U.S. Patents owned by AcornCardiovascular, Inc. (U.S. Pat. Nos. 6,241,654; 6,230,714; 6,193,648;6,174,279; 6,169,922; 6,165,122; 6,165,121; 6,155,972; 6,126,590;6,123,662; 6,085,754; 6,077,218; 5,702,343) show various devices, alsofor treatment of CHF, which typically include a mesh sock-like deviceplaced around the myocardial wall. U.S. Patents to Myocor, Inc. (U.S.Pat. Nos. 6,264,602; 6,261,222; 6,260,552; 6,183,411; 6,165,120;6,165,119; 6,162,168; 6,077,214; 6,059,715; 6,050,936; 6,045,497;5;961,440) show devices for treatment CHF generally using componentsthat pierce the ventricular wall.

None of the documents mentioned above appears to suggest the devices andmethods provided for herein.

BRIEF SUMMARY OF THE INVENTION

This invention is a device and a method for reinforcing the pericardium.Generically, it is made of at least one compliant member having aninterior surface for placement adjacent to or spaced away from theepicardium and an exterior surface for attachment to the interior of apericardium. The compliant member may be conformable in shape to atleast a portion of the epicardium.

The interior surface is adapted to inhibit adhesions or attachment tothe epicardium, e.g., via use of a material that does not substantiallypermit ingrowth with or that resists ingrowth with the epicardium.Suitable choices for materials that functionally provide such resultsinclude various lubricious material, perhaps polymeric, e.g.,fluorocarbon polymers especially those selected from the groupconsisting of polytetrafluoroethylene, ethylene-chlorofluoroethylene,fluorinated ethylene propylene, polychlorotrifluoroethylene,polyvinylfluoride, and polyvinylidenefluoride and certain expandedpolytetrafluoroethylenes (ePTFE). Other suitable lubricious polymersinclude those selected from the group consisting of LLDPE, LDPE, HDPE,polypropylene, and polyamides their mixtures and co-polymers.

The exterior surface functionally adheres to or reacts with or ingrowswith the pericardium in such a way that the resultingpericardium-implant combination is substantially reinforced compared tothe previously existing pericardium. The outer layer, for instance, maycomprise a material for ingrowth into or with or for attachment to oradherence with the pericardium. The exterior surface may comprise amaterial that itself promotes ingrowth, e.g., polyethyleneterephthalate, polyglycolic acid, polylactic acid, reconstitutedcollagen, poly-p-dioxanone, poly(glycolide-lactide) copolymer,poly(glycolide-trimethylene carbonate) copolymer,poly(glycolide-ε-caprolactone) copolymer, glycolide-trimethylenecarbonate triblock copolymer, their block and random copolymers,mixtures, and alloys. Physical mixtures of the biodegradable polymerswith other substantially non-biodegradable materials, (such aspolyolefins or polyfluorocarbons) is desired to preserve to integrity ofthe flexible or compliant member. Particularly desirable are mixtures ofbiodegradable and non-bio-degradable polymeric fibers, perhaps bycoweaving or other suitable manner of making an integrated fabric.

The outer surface may further comprise a material promotingendothelialization, such as an effective hyalonurate salt or one or moreangiogenic materials such as are listed below. Physically, the outersurface may be an independent layer or an integrated layer, a woven ornon-woven polymeric material. The attachment to the outer layer may besimply mechanical, and produced by, e.g., suturing or adhesivelyattaching it to the pericardium. The exterior surface may be textured toassist with ingrowth into the pericardium.

As noted above, the compliant member may comprise a separate innermember and an outer member, e.g., where at least one of the innermembers and the outer members comprises a woven or non-woven fabric.They may be laminated together or with an intermediate between. In someinstances, at least one, of the inner members and the outer members issubstantially non-porous, non-porous, or non-continuous.

It is desirable that the inventive device include an adjuster adaptedfor changing the compliant member size after attachment of thatcompliant member to the interior of the pericardium. The adjuster, forinstance, may be a rotatable roller, a drawstring, a band, or the like.One preferable band variation is made up of an upper end and an apicalend and has a length extending from the upper end to the apical end andwhere the length of the band is less than about ⅓ length of a heart towhich it is applied. The band may have a length substantially matchingthe width of the A-V groove on that heart.

The shape of the compliant member may be that of a sack having a closedend, particularly one having a closed end and sized to be positionedonly along and less than about ⅓ length of the heart when positionedfrom the apical end. The compliant member may be a substantiallyelongated member having a distal end and a proximal end and configuredto be helical upon introduction into the region of the pericardium,perhaps having a lumen (in some instances expandable) extending from theproximal end at least partially to the distal end. The lumen may have atleast one orifice open to the exterior surface when the device ishelically configured in the region of the pericardium, perhaps to passglue or adhesive to the pericardium side of the device. In somevariations, the source of glue or adhesive also forms a component of theinventive device.

One very desirable form of the compliant member is an enclosuregenerally conforming in shape to at least a portion of an epicardiumwhere the enclosure has at least one rib separated by and spaced apartby webbing. The rib may be at least one band having an upper end and anapical end and a length extending from the upper end to the apical endand having at least two open, generally opposing openings. Desirably,the wound band has a length less than about ⅓ length of a heart to whichit is applied.

Preferably, the various ribs have a flexibility different than that ofthe webbing. The at least one rib may have the form of a generallyhelical member, perhaps ribbon-like in form. A “ribbon” is considered tohave a width-thickness ratio greater than about two, perhaps greaterthan about seven. The helical member may be inflatable over at least aportion of the enclosure, perhaps incrementally inflatable along itslength.

The compliant member may be made up of an enclosure generally conformingin shape to at least a portion of a pericardium and having multiple ribsextending from the upper end to the apical end. Desirably each rib maybe ribbon-like. Alternatively, the ribs may each have a round crosssection or may have a cross section with a width-thickness ratio of twoor less. The multiple ribs may be zigzag in shape and where there aremultiple zigzag ribs having substantially adjacent points, at least someof the adjacent points may be connected. At least some of the multipleribs may be joined at the apical end.

The webbing may be of a variety of forms, e.g., a woven fabric, a wovenopen weave fabric, one or more ribbons extending between at least someof the multiple ribs, one or more fibers extending between at least someof the multiple ribs, an elastic material, a substantially inelasticmaterial, or the like.

The compliant member may have a longitudinal opening extending from theupper end towards the apical end and including a plurality of loopingmembers situated on the upper end (like loops on a kitchen curtain)deployable over a looping deployment tool. The deployment tool ispreferably adapted to be removable after placement of the compliantmember adjacent said pericardium and has a connector member forseparation after installation. The invention, in some variations,includes the installation member.

The invention includes various procedures for reinforcing thepericardium. One procedure comprises the steps of introducing theinventive device through a pericardium wall into a pericardial space,desirably below the xiphoid process of a patient, and positioning theinventive pericardial reinforcement adjacent the pericardium. Theprocedure may include the step of puncturing skin beneath the xiphoidprocess with a needle and an introducer and passing the needle throughthe pericardium to the pericardial space. The steps of introducing aguidewire, removing the needle, and introducing a cannula may also beincluded.

Finally, the invention includes a modified pericardium reinforced withthe compliant pericardial reinforcement devices discussed elsewhere.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an anterior view of the heart in a human chest showing thepericardium in particular.

FIG. 2 is a partial cross-section of the inventive reinforcing device asdeployed upon a pericardial sac and in reference to an epicardium.

FIG. 3A shows a cross-sectional view of the compliant member making upone variation of the invention. FIG. 3B shows a side-view of the FIG. 3Amaterial.

FIG. 4A shows a cross-sectional view of the compliant member making tipone variation of the invention. FIG. 4B shows a side view of the FIG. 4Amaterial.

FIGS. 5 and 6 show cross-sectional views of, respectively, mechanicalfasteners and adhesives in placing the inventive device on thepericardium.

FIGS. 7, 8, and 9 show various side-views of variations of theinvention.

FIGS. 1A, 10B, 11A, 1B show side views (FIGS. 10A and 11A) of variationsof the inventive reinforcing member and cross-sectional views (FIGS. 10Band 11B) of those variations.

FIGS. 12, 13, and 14 show side views of variations of the invention.

FIGS. 15A, 15B, 15C, and 15D show close-ups of various webbingvariations suitable for the inventive reinforcing member.

FIGS. 16A, 16B, 17 A, and 17B show, respective, a side-view of avariation of the invention device employing adhesives prior tointroduction into the pericardial sac, a cross section of that sideview, a side view of the variation after introduction to the pericardialsac, and a cross section of that installed device.

FIG. 18 shows a side view of a variation of the inventive device and anintroducer.

FIG. 19 shows a side view of a variation of the inventive device havinga draw-string adjuster.

FIG. 20A shows a side view of a variation of the inventive device havinga roller adjuster. FIG. 20B shows a top view of the FIG. 20A variationschematically depicting the operation of the adjuster.

FIG. 21 shows a side view of a variation of the inventive device alsohaving a draw-string adjuster.

FIGS. 22A-22E show a method for introducing the inventive device intocontact with the pericardium.

DETAILED DESCRIPTION OF THE INVENTION

As noted elsewhere, this invention has several related aspects: it is1.) a device for reinforcing the pericardial sac that has an innersurface that tends not to adhere to the epicardium and an outer surfacethat adheres to, is inter-grown with, or is made in some fashion toconstrain expansion of some portion of the pericardium; 2.) methods ofintroducing the inventive reinforcing device to the operative site; and3.) the resulting modified and reinforced pericardium having theinventive reinforcing device attached to it.

Our use of the term “compliant” and its variations are embodied in thefollowing: in general, the inventive reinforcing device is constructedin such a way that it is sufficiently compliant to be placedinsubstantial contact with a portion of the inner surface of thepericardium to allow some measure of adherence between the two. This maymean that the device is flexible or that a portion of the device isflexible or that a portion of the device is comparatively stiffer thananother portion or portions. The functional result is this: the deviceshould reinforce the pericardium in such a way that over an extendedperiod of time, the size of the combination of pericardium and thereinforcing device do not expand in a way consistent with the typical,ongoing progress of CHF. Additionally, we use the term “substantiallynon-elastic” not in an absolute sense, but simply to express thefunctional concept that during the use of the device in reinforcing thepericardium, the device is not substantially changing in size due to thepressures placed upon it by the beating of the heart. Some elasticity ina gross physical sense is perceived to be inevitable.

First, in FIG. 1, the situation of a typical human heart (100) may beseen. Of special interest here is the pericardium (102) surrounding theepicardium (104) but separated by a small barrier filled with apericardial fluid (106). The pericardial sac or the pericardium (102)approaches the diaphragm (108) closely at the apex of the heart. Inindividuals who are not obese, the distance from the exterior surface ofthe skin, through the diaphragm (108), and into the pericardial sac(102) may be as short as a couple of inches. In obese individuals, thedistance can be much greater, e.g., six inches or more. As will bediscussed below, this sub-xiphoid approach (a percutaneous route asdescribed above, but below the xiphoid process-not shown in FIG. 1) ishighly desirable and even preferable to “cracking the chest” tointroduce various implants into the cardiac space.

Also seen in FIG. 1, for reference are the lungs (110, 112) and the ribs(114). Note how far below the apex at the heart (100) the ribs extend.

FIG. 2 shows, in cross-section, a pericardium (120), reinforced by theinventive reinforcing device (122), surrounding a pericardial space(124) typically filled with a fluid and a heart wall or epicardium(126).

The inventive device (122) has an inner surface (128) and an outersurface (130). In use, the inner surface (128) remains generally orsubstantially separated from the epicardium (126). In construction, theinner surface (128) is adapted not to be susceptible to adhesion to theepicardium. One way to prevent such adhesion is to configure the innersurface of a material or with a surface structure that tends not topermit adhesion with the myocardial tissue of the epicardium (126). Thisfunction may be carried out in several ways. For instance, the surface(128) confronting the epicardium (126) may be coated with a slipperymaterial or comprise a slippery material. The device (122) may bemultilayered and comprise an independent inner layer of a slipperymaterial.

By the terms “adherence” and “adhesion,” we mean that the noted specificcomponent or region of the device is substantially locally immobile withrespect to its related heart tissue. That is to say that it may beadhesively connected to the tissue, mechanically attached to the tissue,ingrown with the tissue, connected using specific mechanical connectors,or other methods of or means for preventing relative motion between thedevice component and the tissue wall.

FIG. 3A depicts a cross-section of a compliant member (150}having aninner non-adhering surface (152) and an outer surface (154). In thisvariation of the invention, the inner surface (152) is coated with amaterial that tends not to form adhesions with the epicardium. Thenon-adhering material may be sprayed on or infused into anothersubstrate having a differing proclivity for adhesion onto heart tissue.In the absence of mechanical or chemical adhesives to the pericardialsac, the concept for this variation is simply that there exist adifferential proclivity for formation of adhesion. The inner surface(152) has a comparatively lower proclivity for adhesion to cardiactissue than does the outer surface.

Incidentally, FIGS. 3A and 3B show a typical woven fabric. The weaveneed not be as loose as is shown in FIG. 3B. It is also within the scopeof this invention to use a random fabric or “non-woven” (as it is knownin the polymer industry) for the single or multiple layers of theinvention device. A non-woven material (162) is shown in FIG. 4B inanother variation of the invention for another purpose, but may becoated or used as a laminate member for the inventive device.

The material used that substantially prevents adhesion to the epicardiummay be one or more polymers such as polyfluorocarbons and polyolefinsselected from the group consisting of polytetrafluoroethylene (PTFE orTFE), ethylene-chlorofluoroethylene (ECTFE), fluorinated ethylenepropylene (FEP), polychlorotrifluoroethylene (pCTFE), polyyinylfluoride(PVF), polyvinylidenefluoride (PVDF), polyethylene (LDPE, LLDPE, andHDPE), and polypropylene. An especially desirable polymer is expandedpolytetrafluoroethylene (ePTFE) that is functionally adapted to inhibitingrowth, e.g., ePTFE having internodal differences less than about 40microns.

Again, they may be applied as an emulsion, dispersion, or solution toanother substrate material or the substrate material may instead be thesubstantially non-adhering material with the other side (154) treated toimprove adhesion.

FIG. 4A shows a cross-section of another variation (156) of theinventive device in which the non-adherent surface (158) is a layerseparate from the layer (160) adjacent the pericardium. The two layers(158) may be laminated together, if so desired. They need not be, sincethe function of the non-adhering side (160) is simply to preventattachment of the epicardium to the inventive device (156). Again, bothlayers (158; 160) may be woven, non-woven, or a mixture as desired bythe designer. FIG. 4B shows a typical “non-woven” fabric type.

Returning to FIG. 2, the surface of the reinforcing device (122)adjacent the pericardium (120) is, in some way, to be generally affixedto that pericardium. FIG. 3A shows a woven fabric member (150) having aside (154) that is adapted to biologically mesh or to ingrow with thepericardium. The adhering surface (154) may just as well be anon-wovensurface.

As is shown in FIG. 4A, the adherent surface (160) may be an independentstructure perhaps fixedly laminated to the generally non-adherentsurface (158).

The exterior or adhering surface may comprise a material that itselfpromotes ingrowth, e.g., polyethylene terephthalate, polyglycolic acid,polylactic acid, reconstituted collagen, poly-p-dioxanone,poly(glycolide-lactide) copolymer, poly(glycolide-trimethyleilecarbonate) copolymer, poly(glycolide-ε-caprolactone) copolymer,glycolide-trimethylene carbonate triblock copolymer, their block andrandom copolymers, mixtures, and alloys. Biodegradable polymers oftenpromote growth of endothelium and neovasculature in the body. Physicalmixtures of the biodegradable polymers with other substantiallynon-biodegradable materials, (such as polyolefins or polyfluorocarbons)are desired to preserve the integrity of the flexible or compliantmember. Particularly desirable are mixtures of biodegradable andnon-biodegradable polymeric fibers, perhaps by coweaving or othersuitable manner of making an integrated fabric. An especially desirablenon-biodegradable polymer is expanded polytetrafluoroethylene (ePTFE)that is functionally adapted to promote ingrowth, e.g., ePTFE havinginternodal differences greater than about 60 microns.

Expanded polytetrafluoroethylene (ePTFE) sheets are available having aninternodal distance gradient between the two sides, e.g., one side at 40microns or less and one side having internodal distances greater thanabout 60 microns. Such a sheet is highly desirable.

The adhering surface of any of the variations disclosed here may betreated to enhance the biological bonding with the compliantreinforcement device. The inventive device may be adapted to promoteangiogenesis adjacent the pericardium. Angiogenesis-promoting materials,particularly those that promote growth of microvasculature, whethersynthetic or natural may be infused into the various components, e.g.,into or onto the polymers of the inventive device adjacent thepericardium. Angiogenic materials include, e.g., collagen, fibrinogen,vitronectin, other plasma proteins, various appropriate growth factors(e.g., vascular endothelial growth factor, “VEGF”), and syntheticpeptides of these and other similar proteins. Other components having aspecific role may be included, e.g., genes, growth factors,biomolecules, peptides, oligonucleotides, members of the integrinfamily, RGD-containing sequences, oligopeptides; e.g., fibronectin,laminin, bitronectin, hyaluronic acid, silk-elastin, elastin,fibrinogen, and the like.

Other bioactive materials which may be used in the invention include,for example, pharmaceutically active compounds, proteins,oligonucleotides, ribozymes, and anti-sense genes. Desirable additionsinclude vascular cell growth promotors such as growth factors, growthfactor receptor antagonists, transcriptional activators, andtranslational promotors; vascular cell growth inhibitors such as growthfactor inhibitors, growth factor receptor antagonists, transcriptionalrepressors, translational repressors, replication inhibitors, inhibitoryantibodies, antibodies directly against growth factors, bifunctionalmolecules consisting of a growth factor and a cytotoxin, bifunctionalmolecules consisting of an antibody and a cytotoxin;cholesterol-lowering agents; vasodilating agents; agents which interferewith endogenous vasoactive mechanisms, and combinations thereof.

In addition, polypeptides or proteins that may be incorporated into oronto the inventive device, or whose DNA can be incorporated, includewithout limitation, proteins competent to induce angiogenesis, includingfactors such as, without limitation, acidic and basic fibroblast growthfactors, vascular endothelial growth factor (including VEGF-2, VEGF-3,VEGF-A, VEGF-B, VEGF-C) hif-1 and other molecules competent to induce anupstream or downstream effect of an angiogenic factor; epidermal growthfactor, transforming growth factor α and β, platelet-derived endothelialgrowth factor; platelet-derived growth factor, tumor necrosis factor α,hepatocyte growth factor and insulin like growth factor; cell cycleinhibitors including CDK inhibitors; thymidine kinase (“TK”) and otheragents useful for interfering with cell proliferation, and combinationsthereof.

In any case, it is also within the scope of this invention to utilizemechanical fasteners or adhesives to join the compliant reinforcingmember to the pericardium. For instance, FIG. 5 shows the reinforcement(170) attached to the pericardium (172) variously with a surgical staple(174) and a suture (176). Other mechanical fasteners such as blindrivets (178) or the like are also suitable and within the scope ofknowledge of the worker in this art.

Similarly, FIG. 6 depicts the use of a biological adhesive based perhapson fibrin or polycyanoacrylate or other similarly operating adhesives(180) to affix the reinforcing device (182) to the pericardium (172).

Having explained the generic functioning of the respective sides of thecompliant reinforcing member, we turn now to a description of physicalvariations of the reinforcing member. They share the desirablefunctionality of preferably being deliverable using percutaneousdelivery methods or minimally-invasive methods.

FIG. 7 shows one such basic form (190) in which the compliant enclosurehas a closed apical end (192) and an optional upper end band (194). Thesack (190) may be woven or non-woven. The material used preferably hassome measure of rigidity, having at least sufficient rigidity to allowan amount of pressure against the enclosing pericardium appropriate tobegin the process of adherence to that pericardium. This stiffness isbalanced against the need for the device (190) to be sufficientlycompliant to allow passage through a cannula, or the like, during theprocedure of introducing the device (190) into the pericardial sac.

A schematic introducer (196) is shown in this variation and in many ofthe other variations discussed herein. Typically the introducer (196)will be a wire or rod having a loop carrying the upper end of thedevice, e.g., band (194) in FIG. 7, during the introducing step. Theloop may then be removed from the heart or may remain with the device asa stiffening member.

The variation (190) shown in FIG. 7 may be sufficiently extensive insize that it extends up to the region of the pericardium adjacent thepulmonary arteries, etc.

FIG. 8 shows a side view of a variation of the inventive pericardialreinforcement (200) having a generally pericardial form due to thepresence of webbing (204). Webbing (204) may be fabric, individualthreads, cords, etc—many of which are discussed elsewhere herein, butdesirably the webbing is formed in such a way as to allow for ease offolding and conformation during delivery of the device near and past theheart's apical end. A schematic delivery wire or introducer (206) isshown.

FIG. 9 shows a side view of a variation of the pericardial reinforcementdevice (210) that is open in the end normally near the apical end of theheart and generally is band-shaped. Optional upper band (212) and lowerband (214) are included. These bands (212,214) are to provide structureto the after more-loosely woven compliant member (216) separating them.This variation (210) is especially suitable for providing support localto the ventricular valves, a region whose reinforcement is especiallyeffective in alienating congestive heart failure. This variationminimizes the mass of material implanted into the heart region, an oftendesirable result. The schematic introducer (218) is shown.

FIGS. 10A and 10B show, respectively, a side view and a topcross-sectional view of another ribbed variation (230). As shown in FIG.10A, this variation (230) includes ribs (232) that extend from an upper(but optional) band (234) to an apical end (236). As may be seen in FIG.10B, the ribs (232) may be semicircular in cross-section although thereis a preference for the exterior of the ribs (232) to be a shapeconformable to the pericardium, the cross-sectional shape of the ribs isnot particularly important. The ribs (232), as shown in FIGS. 10A and10B, may stand alone but preferably are separated and held in place bywebbing (238) of any of the various forms discussed herein.

FIGS. 11A and 11B show, respectively, a side view and a cross-sectionalview of another ribbed variation (250). As was noted just above, theribs (252) are not semi-circular in cross-section but have more of aflat aspect. In this variation, the ribs extend to an apical and (254).A schematic introducer (256) is shown. The ribs (252) may be separatedby webbing (258) if desired.

FIG. 12 shows a side view of a variation (260) having ribs (262) that donot extend to the apical end, but instead stop at a lower band (264) andextend from an upper band (266). As was the case with the othervariations of this type, the ribs may be separated by webbing (268). Anintroducer (270) is shown.

FIG. 13 shows a ribbed variation (280) of the inventive reinforcementmember in which the compliant member has ribs (282) that are zigzag inshape. This rib variation minimizes the amount of material that isintroduced as rib material but distributes the stiffer reinforcingmaterial around the periphery of the devices quite nicely. The ribs(282), again, may be separated by webbing (284) material of the typediscussed elsewhere. An introducer (286) is also shown. The ribs (282)are shown to be situated “in phase” but need not be. Other convolutedforms to the ribs, e.g., sine shaped ribs, -shaped ribs, etc., are alsowithin the scope of the invention.

FIG. 14 shows a side view of a variation (290) of the invention wherethe ribs (292) are joined at their respective apexes. The ribs (292)thereby form a continuous cage about the reinforcing member (290). Thevarious spaces (294) remaining amongst the ribs (292) may be filled withwebbing if so desired.

FIGS. 15A-15D show a number of variations of the “webbing” discussedabove.

FIG. 15A shows a number of ribs (300) separated by and held together bystrands (302) of an appropriate material. The strands (302) collectivelymaking up the webbing may be single threads or collections of threadsmaking up a cord-like assemblage.

FIG. 15B shows the ribs (300) with a woven cloth (304) as the webbingmaterial. The relative pic value may be in a range that extends betweenclosed cloth to very open weave.

FIG. 15C shows the ribs (300) with anon-woven fabric (306) havingoptional upper and lower bands (308).

Finally; FIG. 15D shows ribs (300) separated by webbing (310) that ismade up of a series of tapes (310) in turn formed from a fabric, wovenor non-woven.

In addition to the generally pre-formed structures discussed above, wecontemplate structures formable within the pericardial sac.

FIGS. 16A and 16B show, respectively, a side view and a cross-sectionalview of a reinforcing device (320) prior to introduction into thepericardium. FIGS. 17 A and 17B show, respectively, a side view and across-sectional view of the FIGS. 16A and 16B device after deployment.

FIG. 16A shows a side vision of a device (320) having a perforated side(322) with perforation (324). Perforations (324) communicate withinflatable lumen that is not visible in FIGS. 16A and 16B. A deliveryconduit (328) is provided for introducing suitable adhesives into thedevice (320) in the lumen between perforated side (322) and back side(326 in FIG. 16B). Delivery conduit (328) desirably is used as anintroducer for placement of the device (320) in the pericardial sac viaa percutaneous or minimally invasive procedure.

The form of the device (320) shown in FIG. 16A is adapted to allow“corkscrewing” of the device as it is wound though the pericardialspace. In addition, the perforated side (322) is allowed by thisadaptation to migrate to the outside or pericardial side of theresulting structure. Once the proper positioning of the device (320) hasbeen accomplished, adhesive (330) is brought into the lumen between theperforated side (322) and the opposite side (326). The adhesive flowsthrough the perforation (324) to cause adherence between the device(320) and the surrounding pericardial wall.

FIG. 18 shows a variation of the reinforcing member (340) that is not acontinuous band about the heart, in that it has a longitudinal openingfrom upper to apical end and a delivery introducer (342) that may beremoved after delivery of the reinforcing member (340) to thepericardium. Optionally, the elongate section (344) of the deliveryintroducer (342) may be separately removed.

All of our variations are passive devices.

After a period of time, it may be desirable to alter the stiffness ofthe inventive reinforcing device. Because the device is preferablyadherent to or ingrown with the pericardium, replacement is not adesired step. Simple size adjustment would be. FIGS. 19, 20A, 20B, and21 show various features allowing for adjustment of some size of theinstalled pericardial reinforcement device.

FIG. 19 shows a simple or generic reinforcing device (350) similar instructure and concept to that found in FIG. 9. An added feature is thestructure of the lower band (352) and its attendant drawstring (354).The lower band (352) has a lumen that circumscribes the lower end of thedevice (350). The drawstring (354) passes through this circumscribinglumen. It is desirable to place radio-opaque markers (386), e.g.,platinum or gold bands, on the drawstring (354) to allow for laterdetection and manipulation. The concept is simple: to pull on thedrawstring (354) either both sides together or one side against theother, thereby, to cinch the lower band into a smaller diameter. Somedesign thought must be had to permit the drawstring (354) to slidewithin the lower band (352), e.g., by proper choice of materials on thisportion. Tugging on the drawstrings (354) of the heart will tighten thepericardium and provide additional firmness to that pericardium inslowing the progression of CHF. The drawstring (354) may be situated sothat it is adjustable from within or without the pericardial space.

FIGS. 20A and 20B show a tightener variation in which the reinforcementdevice (360) includes a rotatable spine (362) that is affixed to thecompliant member (364) that, in turn, is adherent to the pericardium.Twisting of the spine (362) tightens the reinforcement device and hencethe pericardium. Desirably, the spine (362) may be twisted from thepericardia! space near the apex of the enclosed heart.

FIG. 20B schematically shows the twisting of spine (362).

FIG. 21 shows a variation (370) similar in structure to that shown inFIGS. 10A and 10B. Each of these variations includes ribs (372 in FIG.21 and 232 in FIGS. 10A and 10B) that meet at an apex. The ribs (372)may be fixed together at that apex (374) or may flex freely about thatlower point. In either case, the drawstring (376) in the lumen upperband (378) may be tightened to close the upper band (378) and to tightenthe structure of inventive device (370). Again, use of radio-opaquemarkers (380) is highly desirable. The drawstring (376) should be placedso to be accessible to the pericardial space.

Several of the benefits extending from the inventive device may besummarized in the following way: Our device is intended notsubstantially to contact the epicardium in normal use. Consequently,many of the problems inherent simply in the act of contacting themyocardial tissue, e.g., arrhythmia, myocarditis, etc., may beminimized. Because our implant is designed not substantially to contactthe epicardium, any consequent coarsening of the epicardial tissue islessened.

The pericardium is in a gross engineering sense, a liquid-filled shockabsorber that tends to exert a constant force upon the epicardium thatis assessable via the fluid pressure in the pericardial space. Thispressure is in some measure, related to the fitness and strength of thepericardium. Placement of implants upon the epicardial surface providessupport to that surface, but the support is at the cost of directimplant contact. Our device provides the same or similar support in amuch more gentle and uniform way, by supporting the pericardium andthereby supporting the fluid that supports the heart.

Additionally, sizing and placement of the pericardial reinforcement issomewhat simpler in that the object of the placement procedure is notactively beating but is only a membrane that is passively affected bythe beating muscle.

One highly desirable method for placement of the inventive reinforcementis shown in FIGS. 22A-22E.

This inventive device is neat and, because it is situated in contactwith the pericardium, is suitable for placement via any number ofprocedures, ranging from the most invasive—open chest surgery—to thosethat are much less invasive. A preferred procedure for placing thedevice is via a percutaneous approach through the diaphragm beneath thexiphoid process. The procedure is direct and uses short instruments forease and accuracy. Such a process is outlined in FIGS. 22A-22F.

Shown in FIG. 22A is a heart (400) surrounded by a pericardia! space(402) holding pericardia! fluid and all is enclosed by the pericardium(404). Also shown is the muscle sheet known as the diaphragm (406). Forthe purposes of depicting the spatial relationships in this procedure,the xiphoid process (510) is shown in shadow. Much of the extraneousbody structure not otherwise needed for explanation of the procedurehave been omitted for clarity.

Also shown in FIG. 22A is the first step of the procedure. A suitablylarge hollow needle (408) and a guidewire (410) passing through thelumen of the needle (408) have been introduced below the xiphoid processand through the diaphragm (406). The needle (408) and the guidewire(410) are shown having penetrated the pericardium (404) and havingpassed into the pericardial space (402).

FIG. 22B shows that the needle has been removed from the guidewire (410)and the distal end (412) of the guidewire (410) has been manipulated topass upwardly. An introducer or cannula (414) is shown being passed upthe guidewire (410).

In FIG. 22C, a cannula (420) has been placed through the pericardium(404) and the introducer wire (422) has been inserted and may be seenproceeding to the left of the heart. The reinforcing device (424) beginsto trail the introducer wire (422). In this variation, the upper band(426) has a relatively rigid connection with the introducer (422) andwill tend to move the device about the apex of the heart (400).

Some amount of manual manipulation will be necessary to keep the upperloop (426) following “the contours of the epicardium until it reachesits desired site as shown in FIG. 22D. A vibratory or oscillatory motionmay be desirable to urge the device to its final spot.

In FIG. 22E, the introducer wire (422) and cannula (420) have beenremoved and their access points repaired, leaving the device (424)against the pericardia! membrane (404) for attachment, adherence, oringrowth.

Many alterations and modifications may be made by those of ordinaryskill in this art, without departing from the spirit and scope of thisinvention. The illustrated embodiments have been shown only for purposesof clarity and the examples should not be taken as limiting theinvention as defined in the following claims. Which claims are intendedto include all equivalents, whether now or later devised.

1. A compliant and substantially non-elastic pepcardial reinforcementcomprising a compliant and substantially non-elastic member having aninterior surface for placement adjacent an epicardium, the interiorsurface tending to inhibit adhesions with the epicardium and having anexterior surface for attachment to the interior of a pericardium.